I own/have owned about 40 Nikon lenses. Don't automatically assume the D lenses have a higher build quality. Many have cracking issues with the AF/MF ring, for example.

I've gradually changed almost all my AF-D lenses for AF-S/G lenses. The image quality has ranged from better to vastly superior for the G lenses.

While some talk about the "plastic build", I can tell you the pro lenses are of metal construction with an outside plastic shell - think of it as a protective "bumper". And they hold up quite well - no more "brassing", and scratches are invisible since its the same color throughout the material.